The comet assay of nasal epithelia: measurement of DNA damage for the assessment of genotoxic air pollution

OBJECTIVES: The alkaline single cell gel electrophoresis or "comet" assay allows measurement of DNA damage in single cells with a high degree of sensitivity, e.g., for investigations of the effect of environmental agents with DNA-damaging potential. This study aimed to adapt this test to respiratory cells of the human nasal mucosa to examine the genotoxic effect of air pollution (cigarette smoke). STUDY DESIGN: In a prospective study, nasal epithelia of 16 cigarette smokers were examined by the adapted comet assay and the results were correlated with the results of the Papanicolaou-stained nasal cytology, carried out in a blinded fashion. The control group comprised 20 non-smoking men. All subjects under investigation were healthy office workers. METHODS: Nasal epithelia were harvested from the maxilloturbinates. One part of cells was Papanicolaou stained and evaluated by cytopathologists. The comet assay was performed on the other part of the cells. The examiners were blinded to the study and control groups. RESULTS: Among cigarette smokers, a significant correlation between cytopathological cell nucleus changes (metaplasia and dysplasia) and the DNA migration (tail lengths) in the comet assay was found as a sign of DNA damage. This was not found in nonsmoking control persons. CONCLUSIONS: These results confirm the sensitivity of the comet assay and the hypothesis that cell nucleus changes in conventional nasal cytology are associated with DNA damage.     

Increased burden of respiratory disease in the first six months of life due to prenatal environmental tobacco smoke: Krakow birth cohort study

The main purpose of our study was to assess the effects of prenatal tobacco smoke on respiratory symptoms and on doctor consultations in a birth cohort of 445 infants who had no smoking mothers and who had no postnatal exposure to environmental tobacco smoke (ETS). Before and after delivery, questionnaires and interviews with mothers were administered to solicit information on prenatal and postnatal ETS exposure. Newborns were followed-up over six months of life, and respiratory outcomes such as runny or stuffed nose, cough with or without cold, difficult (puffed) breathing, wheezing or whistling in the chest irrespective of respiratory infection were considered. In addition, medical visits related to the occurrence of respiratory symptoms were recorded for each child over a six-month study period. In the multivariate Poisson regression analysis, a set of potential confounders has been taken into account such as gender of child, season of birth, gestational age, maternal education, maternal atopy, presence of moulds in households and prenatal level of personal exposure to fine particles. The adjusted rate ratio (RR) estimated for the occurrence of episodes of running nose was significantly higher in infants exposed to prenatal ETS (1.40; 95% confidence interval [CI]: 1.11-1.68) and the corresponding RR estimates for cough, difficult breathing and wheezing were 1.49 (95% CI: 1.15-1.93), 1.96 (95% CI: 1.22-3.16) and 5.12 (95% CI: 2.86-9.16). The rate ratios of doctor consultations attributable to prenatal ETS because of cough was 1.94 (95% CI: 1.49-2.54). The risk estimate for consultations due to difficult breathing was 2.77 (95% CI: 1.76-4.36), and that for wheezing was 5.86 (95% CI: 3.56-9.64). The data strongly support the view about the impact of the in-utero effect of passive smoking on children's respiratory health. Higher utilization rates of doctor consultations in infants attributable to prenatal ETS exposure demand the revision of public health policy, which should be focused also on cessation of smoking practices by all household members during and after the pregnancy period.     

Cigarette smoking and risk of epithelial ovarian cancer (Australia)

Objectives: We studied the association between cigarette smoking and ovarian cancer in a population-based case–control study. Methods: A total of 794 women with histologically confirmed epithelial ovarian cancer who were aged 18–79 years and resident in one of three Australian states were interviewed, together with 855 controls aged 18–79 years selected at random from the electoral roll from the same states. Information was obtained about cigarette smoking and other factors including age, parity, oral contraceptive use, and reproductive factors. We estimated the relative risk of ovarian cancer associated with cigarette smoking, accounting for histologic type, using multivariable logistic regression to adjust for confounding factors. Results: Women who had ever smoked cigarettes were more likely to develop ovarian cancer than women who had never smoked (adjusted odds ratio (OR) = 1.5; 95% confidence interval (CI) = 1.2–1.9). Risk was greater for ovarian cancers of borderline malignancy (OR = 2.4; 95% CI = 1.4–4.1) than for invasive tumors (OR = 1.7; 95% CI = 1.2–2.4) and the histologic subtype most strongly associated overall was the mucinous subtype among both current smokers (OR = 3.2; 95% CI = 1.8–5.7) and past smokers (OR = 2.3; 95% CI = 1.3–3.9). Conclusions: These data extend recent findings and suggest that cigarette smoking is a risk factor for ovarian cancer, especially mucinous and borderline mucinous types. From a public health viewpoint, this is one of the few reports of a potentially avoidable risk factor for ovarian cancer.     

氯喹对烟雾吸入伤大鼠肺细胞膜ATP酶活性和丙二醛含量的影响

目的：探讨氯喹对烟雾吸入伤大鼠肺细胞膜ＡＴＰ酶活性及丙二醛含量的影响,方法：８０只Ｗｉｓｔａｒ大鼠随机分成正常对照组,烟雾吸入伤１,３,６,１２和２４ｈ组以及氯喹治疗６ｈ和１２ｈ组,分别于各时相点活杀动物,取肺制备膜制剂,用生化比色法测定膜上Ｎａ＾＋,Ｋ＾＋－ＡＴＰ酶Ｍｇ＾２＋－ＡＴＰ酶和Ｃａ＾２＋－ＡＴＰ酶活性,用比色法测定膜上丙醛含量,并用定磷法测定膜总磷脂含量,结果：烟雾吸入伤后,肺细胞膜３     

氯喹、地塞米松对烟雾吸入伤大鼠肺细胞膜损伤的影响

目的　观察氯喹、地塞米松对烟雾吸入伤大鼠肺细胞膜损伤的影响。方法　健康 Ｗｉｓｔａｒ 大鼠１００ 只随机分成正常对照组,吸入伤１ ｈ 、３ ｈ 、６ ｈ 、１２ ｈ 和２４ ｈ 组,氯喹治疗６ ｈ和１２ ｈ 组以及地塞米松治疗６ ｈ 和１２ ｈ 组。实验毕活杀动物,取肺组织制备细胞膜。提取膜磷脂,并用高效液相色谱仪测定磷脂组份,用荧光偏振法测定膜流动性,用生化比色法测定细胞膜 Ｎａ＋ , Ｋ＋ Ａ Ｔ Ｐ 酶、 Ｃａ２ ＋ Ａ Ｔ Ｐ 酶和 Ｍｇ２ ＋ Ａ Ｔ Ｐ酶活性。结果　烟雾吸入伤后,细胞膜磷脂酰胆碱（ Ｐ Ｃ） 、磷脂酰乙醇胺（ Ｐ Ｅ） 和磷脂酰肌醇（ Ｐ Ｉ） 明显降低,同时伴有膜荧光偏振度（ρ） 和膜平均微粘度（η） 明显增加及３ 种 Ａ Ｔ Ｐ 酶活性降低（ Ｐ＜ ００５ ～ Ｐ＜ ００１） 。与吸入伤６ ｈ 组相比,氯喹治疗６ ｈ 组动物 Ｐ Ｃ、 Ｐ Ｅ 含量明显增加,同时降低ρ和η,并增加 Ｎａ ＋ , Ｋ＋ Ａ Ｔ Ｐ 酶和 Ｃａ２ ＋ Ａ Ｔ Ｐ 酶活性（ Ｐ＜ ００５ ～ Ｐ＜ ００１） ,而地塞米松治疗６ ｈ 动物仅增加 Ｐ Ｅ 含量、降低ρ和η,但对膜上 Ａ Ｔ Ｐ 酶活性无影响。结论　烟雾吸入可引起肺细胞膜受损,膜流动性及膜 Ａ Ｔ Ｐ 酶活性降低,而氯?     

Genetic polymorphisms of N-acetyltransferase 1 and 2 and risk of cigarette smoking-related bladder cancer.

Aromatic amines from cigarette smoking or occupational exposure, recognized risk factors for bladder cancer, are metabolized by N-acetyltransferases (NAT). This study examined the association of (NAT) 1 and 2 genotypes with the risk of smoking-related bladder cancer. A total of 74 pathologically confirmed bladder cancer patients and 184 controls were serially recruited from the National Taiwan University Hospital. History of cigarette smoking and other risk factors for bladder cancer was obtained through standardized questionnaire interview. Peripheral blood lymphocytes were collected from each subject and genotyped for NAT1 and NAT2 by DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism methods. Allele frequency distributions of NAT1 and NAT2 were similar between cases and controls. There was a significant dose-response relationship between the risk of bladder cancer and the quantity and duration of cigarette smoking. The biological gradients were significant among subjects carrying NAT1*10 allele or NAT2 slow acetylators, but not among NAT2 rapid acetylators without NAT1*10 allele. The results are consistent with the hypothesis that NAT1 and NAT2 might modulate the susceptibility to bladder cancer associated with cigarette smoking.     

A case–control study of lung cancer and environmental tobacco smoke among nonsmoking women living in Shanghai, China

Introduction: The incidence of lung cancer in women living in China is among the highest in the world but it does not appear that tobacco smoking is a major risk factor for lung cancer. As tobacco smoking is highly prevalent in Chinese men, exposure to environmental tobacco smoke (ETS) may play an important role in the development of lung cancer in Chinese women who never smoked. We conducted the present investigation because previous studies did not account for dietary habits or indoor air pollution from Chinese-style cooking and they did not assess the effect of occupational exposure to ETS.Methods: A population-based, case–control study was conducted to evaluate the relationship between lung cancer and exposure to ETS among nonsmoking women living in Shanghai, China. Five-hundred and four women diagnosed with incident, primary lung cancer between February 1992 and January 1994 were identified through the population-based Shanghai Cancer Registry. A control group of 601 nonsmoking women was selected randomly from the Shanghai Residential Registry, and was approximately frequency-matched to the age distribution of the lung cancer cases. Information on lifetime domestic and occupational exposure to ETS was obtained through face-to-face interviews. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated by unconditional logistic regression.Results: The OR for ever exposed to ETS from spouses was 1.1 (95% CI: 0.8–1.5), and the OR for ever exposed to ETS at work was 1.7 (95% CI: 1.3–2.3). Furthermore, the OR increased with increasing number of hours of daily exposure to ETS in the workplace and with increasing number of smoking co-workers. No associations were found for exposure to ETS during childhood.Conclusions: The main findings of the present study are that long-term occupational exposure to ETS, both alone or in combination with exposures at home, conferred an increased risk of lung cancer among women who never smoked. The inconsistency of the results regarding exposure to ETS at home and at work may have been due to lower exposures at home.     

The duration of maternal cigarette smoking, fetal and placental disorders

Data from a large prospective study of pregnancy were used to determine whether the number of years a mother had smoked cigarettes influenced the development of common fetal and placental disorders. Three disorders increased in frequency when mothers had smoked for more than 6 yr: placenta previa +143%, abruptio placentae +72% and large placental infarcts +37% (all P less than 0.05). Mothers' current smoking habits had a smaller influence on the frequency of these disorders, and the effects of smoking were largely independent of maternal pregnancy weight gain. The placentas of smokers had microscopic evidences of underperfusion from the uterus. The placental abnormalities were influenced by both the number of years mothers had smoked and by their current smoking habits.     

Impact of Environmental Tobacco Smoke on Children With Asthma,United States, 2003–2010

ObjectiveGiven widespread interventions to reduce environmental tobacco smoke (ETS) exposure and improve asthma control, we sought to assess the current impact of ETS exposure on children with asthma.MethodsWe analyzed 2003–2010 data for nonsmoking children aged 6 to 19 years with asthma from the National Health and Nutrition Examination Survey. Outcomes (sleep disturbance, missed school days, health care visits, activity limitation, and wheezing with exercise) were compared between ETS exposed children (serum cotinine levels 0.05 to 10 ng/mL) and unexposed children (<0.05 ng/mL) using ordinal regression adjusted for demographic characteristics. We also assessed whether associations were observable with low ETS exposure levels (0.05 to 1.0 ng/mL).ResultsOverall, 53.3% of children aged 6 to 19 years with asthma were ETS exposed. Age-stratified models showed associations between ETS exposure and most adverse outcomes among 6- to 11-year-olds, but not 12- to 19-year-olds. Even ETS exposure associated with low serum cotinine levels was associated with adverse outcomes for 6- to 11-year-olds. Race-stratified models for children aged 6 to 19 years showed an association between ETS exposure and missing school, health care visits, and activity limitation due to wheezing among non-Hispanic white children, and disturbed sleep among non-Hispanic white and Mexican children. Among non-Hispanic black children, there was no elevated risk between ETS exposure and the assessed outcomes: non-Hispanic black children had high rates of adverse outcomes regardless of ETS exposure.ConclusionsAmong children with asthma 6 to 11 years of age, ETS exposure was associated with most adverse outcomes. Even ETS exposure resulting in low serum cotinine levels was associated with risks for young children with asthma.     

<Emphasis Type="Italic">XRCC1</Emphasis> Arg194Trp polymorphism and risk of chronic obstructive pulmonary disease

The DNA damage, caused by cigarette smoking, can cause airway cell apoptosis and death, which may be associated with the development of chronic obstructive pulmonary disease （COPD）. However, just 20%-30% smokers develop COPD, which suggests that different degrees of DNA repair cause different outcomes in smokers. X-ray repair cross-complementing group 1 （XRCC 1）, a base excision repair protein, has multiple roles in repairing ROS-mediated, basal DNA damage and single-strand DNA breaks. The present study investigated the association between polymorphism in XRCC1 （Arg399Gln） and susceptibility of COPD. A total of 201 COPD cases and 309 controls were recruited and frequency-matched on age and sex. XRCC1 genotype was determined by PCR-restriction fragment length polymorphism analysis. Overall, compared with those with the XRCC1 Arg/Arg genotype, the risk for COPD had no significant difference among individuals with Trp/Trp genotype. However, after stratifying by smoking status, in former smokers, compared with those with the XRCC1 Arg/Arg genotype, the risk for COPD was significantly reduced among individuals with Trp/Trp genotype （adjusted OR=0.22, 95% CI 0.06-0.85, P=0.028）; after stratifying by smoking exposure, in light smokers, compared with those with the XRCC1 Arg/Arg genotype, the risk for COPD was significantly reduced among individuals with Arg/Trp genotype and Trp/Trp genotype （adjusted OR=0.39, 95% CI 0.16=0.94, P=0.036; 0.24, 95% CI 0.07-0.79, P=0.019, respectively）. In conclusion, XRCC1 Arg194Trp genotype is associated with a reduced risk of developing COPD among former and light smokers.